Interlaced and non-interlaced (or progressive) image formats are two general image formats. An interlaced image can be converted into a non-interlaced image by a de-interlacing operation. As an interlaced image lacks comparable pixel data at the same pixel positions of two adjacent frames, motion estimation is developed to implement the de-interlacing operation. Motion estimation is the process of determining motion vectors that describe the transformation from one 2D image to another. For de-interlacing, motion estimation is block-based and differences among blocks are used for the estimation.
However, for some interlaced images involving special patterns, motion estimation may cause serious distortion of images. Then it is improper to implement the de-interlacing operation with motion estimation in such cases. For error protection, it is desirable to develop an image-processing method and an image-processing device which can identify such interlaced images in advance and use adaptive de-interlacing algorithms.